1. Field of the Invention
The present invention relates to a motor actuator used for an automotive air conditioning system and the like.
2. Description of the Related Art
In an automotive air conditioning system, a plurality of doors are provided midway in an air passage, through which air flows, and a driving motor actuator is attached to the door. The opening degree of the door is controlled by the motor actuator and thereby, for example, the quantity of air blowing into a vehicle's compartment (vehicle interior) is regulated. In this type of motor actuators, a potentiometer for detecting the rotational position of an output shaft is used for the purpose of controlling the rotational position thereof (see Reference (1) in the following Related Art List, for instance).
The potentiometer includes a rotation detection pattern, which is used to generate a detection signal indicating the rotational position of the output shaft, and a brush, which is in contact with the rotation detection pattern. In general, the rotation detection pattern is formed in a circuit board held within a housing, and the brush is so provided as to be rotatable integrally with an output gear of the output shaft. As the output shaft rotates, a contact position of the rotation detection pattern and the brush changes according to the rotational position of the output shaft. As a result, a detection signal in response to the rotational position of the output shaft is outputted from the rotation detection pattern.